The parking police in San Francisco always seem to know when a car has stayed just seconds too long at a curb or a meter has gone unfed. They have license plate readers and other tools to detect errant vehicles.

But what if there was a way to track the parking officers themselves?

Last week, a website went viral after it showed icons with the initials of San Francisco’s parking police and the exact locations of their little white vehicles, from which they collectively issued a ticket every 24 seconds. The site worked for only four hours but prompted numerous headlines and generated social media buzz.

It was the latest handiwork of Riley Walz, a 23-year-old software engineer, who managed to reverse engineer the city’s parking ticket system to track every ticket moments after it was slapped on a car windshield.

“I made a website,” he wrote on X. “AVOID THE PARKING COPS.”

In a city that has long embraced eccentrics and their wacky ideas — and serves as the promised land for 20-somethings with cutting-edge tech skills — Mr. Walz is right at home. And he seems determined to keep punking San Francisco.

By day, Mr. Walz works with start-ups to help them create data projects. He also runs Numerous.ai, a site he co-founded that uses chatbots inside spreadsheets. It’s the kind of work that might otherwise make him an anonymous figure in the Bay Area.

But Mr. Walz has found fame another way. While some tech figures here are known for their luxurious homes or their IPO riches, Mr. Walz has made his mark as a pesky prankster.

There was the time he created a fake Manhattan steakhouse on Google Maps and then opened it as a real one — for one night only.

There was the time he used artificial intelligence to rate restaurants according to how hot their customers were. And the time he created The Panama Playlists, a website revealing the Spotify listening habits of well-known people. (Now we know that Vice President JD Vance likes the Backstreet Boys’ “I Want It That Way.”)

There have been more exploits. So many more.

In an interview in the living room of his North Beach apartment, with stunning views of the city’s northern waterfront and the twinkling lights of Telegraph Hill, Mr. Walz made some confessions.

For starters, he doesn’t need tech skills to pull off a good prank. A few months ago, in the middle of the night, he affixed large signs declaring “Coming 2026, Chick-fil-A” on a long vacant, burned-out building near his apartment. Considering the fast-food chain’s conservative bent (it is still closed on Sundays so employees can go to church) and San Francisco’s liberal one, people promptly shared photos on Reddit and expressed their disdain.

“No way in hell San Francisco lets this happen,” one commenter posted. Others simply left barfing emojis. The signs were removed quickly.

Two years ago, he posed as a reporter to sneak into a City Hall gala that was hosted by then-Mayor London Breed for international journalists who were covering the Asian-Pacific Economic Cooperation conference.

He made a fake email address, claiming to be with a media outlet called I.L.C.E., which secretly stood for “I Like to Crash Events.” He managed to dupe security officials, and he has a photo with Ms. Breed, who was wearing a hot pink suit, to prove it.

Also in the photo is Mehran Jalali, Mr. Walz’s fellow prankster, co-founder of Numerous.ai and roommate. He is also the person for whom the fake steakhouse was named.

“One of our friends joked that when Andy Warhol said everybody will be famous for 15 minutes, he forgot to say that Riley Walz will do it a million times over,” Mr. Jalali said.

Their apartment held more clues to other pranks. A sign on the wall that looked like an official city sign stated, “Notice: Stolen Goods Must Remain Under $950.”

Mr. Walz and another friend posted those placards outside Louis Vuitton in the city’s upscale Union Square shopping district to mock a state law, since overturned by voters, that considered the shoplifting of goods a misdemeanor if they totaled less than $950. That threshold had become a regular talking point for conservatives and other critics of California cities, who attacked it as an indication the state was too soft on crime.

The signs went viral and more media attention followed.

Some of his ideas work better than others.

Less successful? After the chief executive of UnitedHealthcare was shot dead on a Manhattan street, police initially said the killer had fled on a rented Citi Bike. Mr. Walz had already been scraping Citi Bike data for a different project and tried to determine which bike the shooter was on and where he was headed.

It turned out that the suspect, later identified as Luigi Mangione, had fled on a different type of bike. Mr. Walz said that when he posted on social media about his search for the shooter, people called him “a bootlicker” for helping the authorities and threatened his safety.

Mr. Walz grew up in Ballston Spa, N.Y., north of Albany. His mother is a second-grade teacher, and his father works for a government contractor on a naval base.

Mr. Walz was always whip smart, recalled his mother, Stacey Walz. She noted that he was voted Most Likely to Win a Nobel Prize in his high school yearbook. As a teenager, he successfully created the persona of a fake politician, Andrew Walz, a Republican from Rhode Island, who received a blue verified check mark on Twitter in the days before users paid to be verified. (That was covered by CNN.)

Ms. Walz said she was both proud of her son and worried he will end up in jail.

“I’m really scared. I know he’s just on the brink,” she said. “But of all the people in the whole world, he inspires me.”

His brash antics belie his quiet demeanor. He said he taught himself to code and studied business in college before he dropped out to pursue a career in tech. He moved to San Francisco two years ago.

He has a passion for channeling his skills and curiosity into side projects for his own amusement, but also to keep himself sharp.

“You have to follow through on your ideas because if you don’t, you might stop having them,” he explained. “It’s like a muscle you have to keep using.”

Mr. Walz said he got the parking ticket idea after seeing another roommate receive several citations. He said that he is not “anti-parking cop” but just found the data interesting. The city employs 325 parking control officers whose 1.3 million tickets last year brought in $96 million.

The city had provided online access to images of parking tickets so that recipients could review them and pay their penalties. In theory, one had to know the identification number of each ticket to see it. But Mr. Walz was able to view all of the tickets after he figured out the pattern that the city had used to number them, and the data included officers’ initials and badge numbers.

His site included a leaderboard showing which officers were generating the most revenue for the city. The San Francisco Municipal Transportation Agency, which is responsible for city parking enforcement, quickly moved to hide the badge numbers and initials from its tickets, rendering his site useless.

“What unfolded with this website directly involved our employees and put their safety at risk, and that’s not OK,” said Parisa Safarzadeh, a spokeswoman for the agency.

Mr. Walz has never faced any penalties or criminal allegations for his pranks, including his most recent one. He said he hoped it would stay that way.

He would not say much about his future plans. One might involve scraping the city’s graffiti data, he suggested, and another might involve a bunch of mannequins he bought from the now-shuttered Bloomingdale’s downtown for $15 apiece.

Mr. Walz said San Francisco’s small size (population 842,000) makes it easier for him to stand out than in New York. But it may simply be the perfect match of a town and its resident troublemaker.

“He’s at the intersection of whimsy and tech,” Mr. Jalali said, “so this is the ideal city for him.”